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Subject[net-next, 1/3] seg6: verify srh pointer in get_srh()
Date
pskb_may_pull may change pointers in header. For this reason, it is
mandatory to reload any pointer that points into skb header.

Signed-off-by: Andrea Mayer <andrea.mayer@uniroma2.it>
---
net/ipv6/seg6_local.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/net/ipv6/seg6_local.c b/net/ipv6/seg6_local.c
index 9d4f75e0d33a..e187dec2eed1 100644
--- a/net/ipv6/seg6_local.c
+++ b/net/ipv6/seg6_local.c
@@ -75,12 +75,16 @@ static struct ipv6_sr_hdr *get_srh(struct sk_buff *skb)
return NULL;

srh = (struct ipv6_sr_hdr *)(skb->data + srhoff);
-
len = (srh->hdrlen + 1) << 3;

if (!pskb_may_pull(skb, srhoff + len))
return NULL;

+ /* note that pskb_may_pull may change pointers in header;
+ * for this reason it is necessary to reload them when needed.
+ */
+ srh = (struct ipv6_sr_hdr *)(skb->data + srhoff);
+
if (!seg6_validate_srh(srh, len))
return NULL;

--
2.20.1
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